Vane diffuser


  • The vane diffuser is an alternative to the double volute design we find in some larger centrifugal pumps. It consists of a number of vanes set in the volute, around the impeller.
  • The flow from the vanes diffuser is collected in a volute or circular casing and discharged through the pipe outlet. The affect of all of this is to reduce the radial deflection of the shaft of a centrifugal pump when it is operating off of its best efficiency point (BEP).
  • The number of diffuser vanes is normally chosen to be one more than the number of vanes on the impeller to prevent circulation around the vanes resulting from an uneven impeller channel discharge. Although it doesn’t prevent this entirely it does reduce the chances greatly.